Wilson Audio Specialties Sasha DAW loudspeaker Measurements

Sidebar 3: Measurements

Because of the Wilson Sasha DAW's bulk and weight—as well as the fact that Sasha Matson's listening room is on the second floor of his upstate New York home—I drove my test gear the 230 miles from my Brooklyn home to measure the speakers in situ. (I also wanted to hear the Wilson speakers driven by his McIntosh MC462 amplifier, which had impressed me when I measured it for our May 2019 issue.)

As always, I used DRA Labs' MLSSA system and a calibrated DPA 4006 microphone to measure the Sasha DAW's frequency response in the farfield and an Earthworks QTC-40 mike for the nearfield responses. When testing a loudspeaker, I raise it off the floor so that the tweeter is midway between the ceiling and floor. This maximizes the anechoic time window, hence the midrange resolution, of the FFT-based response measurements. Sasha M and I managed to lift one of the 236lb Sasha DAWs onto a small dolly, to make it easier to move it as necessary, but the inevitable reflection of the speaker's sound from the floor reduces the accuracy of my measurements in the midrange.

With that caution in mind, Wilson specifies the Sasha DAW's sensitivity as 91dB/W/1m. My estimate was slightly lower, at 89.5dB(B)/2.83V/m, but this is still usefully higher than average. The nominal impedance is 4 ohms with a minimum value of 2.48 ohms at 85Hz. My measurements of the Wilson's impedance magnitude (solid trace) and electrical phase angle (dotted trace) are shown in fig.1. While the impedance remains above 4 ohms above 160Hz, it drops to 2.415 ohms at 84Hz. The electrical phase angle (dashed trace) reaches –41.3° at 57Hz and +25.7° at 34Hz, both frequencies where the magnitude at 4.75 ohms and 5 ohms is relatively low. The Sasha DAW is an easier load than the Sasha W/P, which Art Dudley reviewed in July 2010, but its impedance will still be a challenge for the partnering amplifier. (This would not have been a problem for SM's McIntosh, however.)


Fig.1 Wilson Sasha DAW, electrical impedance (solid) and phase (dashed) (2 ohms/vertical div.).

The impedance traces are free from the small discontinuities that would suggest the presence of panel resonances. The woofer bin was impressively inert, but when I investigated the upper enclosure's vibrational behavior with a plastic-tape accelerometer, I found a high-Q mode at 598Hz at two places on the sidewalls (fig.2). The high Q, the high frequency, and the fact that the affected areas are small all work against there being any audible problems resulting from the presence of this mode.


Fig.2 Wilson Sasha DAW, cumulative spectral-decay plot calculated from output of accelerometer fastened to upper-frequency enclosure sidewall close to the baffle (MLS driving voltage to speaker, 7.55V; measurement bandwidth, 2kHz).

The impedance-magnitude plot has a saddle centered on a low 23Hz, which will be due to the tuning frequency of the large port on the woofer cabinet's rear panel. The two woofers behave identically; the blue trace in fig.3 shows their summed nearfield response, which has its minimum-motion notch at the expected 23Hz. The nearfield response of the port (red trace) peaks at the same frequency and its upper-frequency rolloff is very clean. The woofers cross over to the midrange unit (green trace) around 200Hz with the rollout above that frequency free from any peaks. As with the earlier Sasha, the midrange unit's initial rolloff starts at 400Hz and is very gentle. The port on the rear of the upper enclosure is used to increase the midrange unit's power handling rather than to extend its low-frequency response with a traditional reflex alignment.


Fig.3 Wilson Sasha DAW, acoustic crossover on tweeter axis at 50", corrected for microphone response, with nearfield midrange (green), woofer (blue) and port (red) responses respectively plotted below 500Hz, 350Hz, and 300Hz.

Like other Wilson loudspeakers, the Sasha DAW's upper enclosure is mounted on the woofer bin with spikes and a series of steps at the rear to allow the midrange and tweeter to be aimed at the listener's ears. For the farfield response measurements in fig.3 and the following graphs, I calculated where the microphone should be placed on the tweeter axis at my standard 50" distance. The midrange unit's output on this axis has a slight peak at 1kHz before crossing over to the tweeter (black trace) just below 2kHz and rolling out relatively smoothly. Small peaks in the tweeter's output are balanced by small dips; the overall response trend is even.

The Wilson's farfield response, averaged across a 30° horizontal window centered on the tweeter axis, is shown as the black trace above 300Hz in fig.4. The overall balance is even from the upper bass through to the top of the audioband, though there is a lack of presence-region energy. The black trace below 300Hz in fig.4 shows the sum of the nearfield woofer and port outputs, taking into account acoustic phase and the different distance of each radiator from a nominal farfield microphone position. The usual rise in response in the upper bass that is due to the nearfield measurement technique is absent. I suspect that the Wilson's low-frequency alignment is optimized for definition rather than maximum bass power. With the low tuning frequency of the port, boundary reinforcement will give extension to 20Hz with typical low-frequency room gain. Certainly in my own auditioning of the Sasha DAWs in Sasha M's relatively small room, the bass sounded both full-range and powerful, but with superb leading-edge clarity.


Fig.4 Wilson Sasha DAW, anechoic response on tweeter axis at 50", averaged across 30° horizontal window and corrected for microphone response, with the complex sum of the nearfield midrange, woofer, and port responses plotted below 300Hz.

The Wilson Sasha DAW's horizontal dispersion, normalized to the tweeter- axis response, is shown in fig.5. (Due to the geometric limitations of SM's room, I could only plot the differences in response up to 45° each side of the tweeter axis instead of my usual 90°.) This graph indicates that some of the missing presence-region energy reap- pears to the speaker's sides. The contour lines in this graph are otherwise even, implying stable stereo imaging. In the vertical plane (fig.6), a suckout develops in the crossover region 5° above the tweeter axis. However, there is more energy present between 1kHz and 3kHz 5° below the measurement axis, which suggests I should have placed the microphone a little lower to be on the exact axis intended by Peter McGrath when he set the speakers up in SM's room.


Fig.5 Wilson Sasha DAW, lateral response family at 50", normalized to response on tweeter axis, from back to front: differences in response 45–5° off axis, reference response, differences in response 5–45° off axis.


Fig.6 Wilson Sasha DAW, vertical response family at 50", normalized to response on tweeter axis, from back to front: differences in response 15–5° above axis, reference response, differences in response 5–10° below axis.

This conjecture is confirmed by the Sasha DAW's step response (fig.7), which is almost identical to that of the Wilson Alexia 2 that I reviewed in July 2018. The tweeter's positive-going step arrives first at the microphone but has started to decay before the start of the midrange unit's negative-going step. The optimal blend between the two units' steps occurs a little lower than the axis that I had calculated I should use for the farfield measurements. However, the positive-going decay of the midrange step does blend smoothly with the start of the woofer's step, which indicates an optimal crossover topology. The Wilson's cumulative spectral-decay plot (fig.8) is relatively clean overall, though some low-level delayed energy is present in the treble. There is also some delayed energy associated with the small on-axis peak at 1kHz.


Fig.7 Wilson Sasha DAW, step response on tweeter axis at 50" (5ms time window, 30kHz bandwidth).


Fig.8 Wilson Sasha DAW, cumulative spectral-decay plot on tweeter axis at 50" (0.15ms risetime).

The Sasha DAW's measured performance has much in common with the other Wilson speakers I have measured and indicates a careful balance between frequency and time domains.—John Atkinson

Wilson Audio Specialtie
2233 Mountain Vista Lane
Provo, UT 84606
(801) 377-2233

Bogolu Haranath's picture

There it is ..... The classic BBC dip .......... There is a -5 db BBC dip from 1 kHz to 5 kHz :-) .........

JRT's picture

Adding the Puppy bass bin to the Wilson Audio Tiny Tot (WATT) was a very good idea.

Kii audio now has the BXT bass bin for the Kii3 (the combination is depicted below).

I would like to see active bass bins offered for the Dutch and Dutch 8C and for the KEF LS50.

AaronGarrett's picture

The Grimm LS1s dmf is the best bass I've heard, and a bin added to the LS1. DSP when properly done -- in this case via feedback -- is where it's at.

Bogolu Haranath's picture

Vandersteen Quatro Wood CT speakers (recently reviewed by Stereophile) come with matching amplifiers, and have powered woofer sections ....... Total cost including matching amplifiers, $32,000 :-) .........

jeffhenning's picture

I understand the need for the BXT with the Kii3 system since they add a tremendous amount of headroom to it's low end and allow the cardioid bass system's radiation pattern to go a bit lower.

With the Dutch & Dutch and LS50's, subwoofers are much more beneficial.

I use a pair of Rythmik servo subs in stereo with LS50's to great effect. I'll be adding another pair of subs this coming year.

JRT's picture

Multi-woofer bass bin certainly provides much more swept volume. But it also spreads out the diaphragm surface source in the vertical while moving some of that source nearer the floor, which serves to ameliorate interference from reflection off of the floor, while also spreading excitation of the floor-ceiling room mode fundamental and harmonics.

The Dutch and Dutch 8C has two 8 inch woofers on the rear baffle, and the design intent places those in close proximity to the wall behind the loudspeaker providing as much as +6dB increase in excursion limited SPL from the boundary coupling, essentially equivalent to doubling the swept volume of the woofers. So the D&D-8C does not need a bass bin for more SPL in high double digit frequencies, but could benefit from spreading the source vertically as mention above.

The KEF LS50 has only the one small 5.25 inch midwoofer to provide bass and midrange. While crossing to a subwoofer to provide much more capacity for volume-velocity at low frequencies certainly helps, I think performance would be further improved with the addition of a bass bin with a pair of 7 inch to 10 inch woofers (for DIY, I would suggest pairs of Dayton Audio RS225-8 wired in parallel, the bottom one not too close to floor to reduce excitation of the pressure node at that boundary) to bridge the gap between the little midwoofer and the subwoofer(s), preferably a multiple subwoofer low frequency subsystem augmented by one to several active interference sources such as PSI Audio AVAA C20 active bass traps.

Note that for a driver on an ideal infinite baffle operating at constant SPL (flat frequency response) at lower frequencies where the diaphragm is behaving pistonically and is small relative to wavelength, there is an inverse square relationship between SPL and swept volume, 4x the swept volume at 1/2 frequency (one octave), 100x the swept volume at 1/10 frequency (one decade).

Bogolu Haranath's picture

You may like the new Revel Performa F328Be, $15,000/pair ......... They have 3, 8-inch woofers each ..... Less expensive than Wilson Sasha DAW or Kii Three with BXT or Joseph Pearl3 :-) ........

supamark's picture

Intentional or happy accident? Regardless, liked the review.

Ortofan's picture

... bring on the Dynaudio Confidence 60.

If the less expensive Confidence 30 speakers could induce JVS to enjoy the music of Diana Krall, then who can predict what feats of magic the model 60 might be able to conjure up.

Peter2520's picture

I agree. What Dynaudio has created with the new Confidence serie is unbelievable. I bought Confidence 60 in maj, and I´m going to a concert every day since.:-) The facilities with Dynaudio´s Jupiter is incredible. I have seen it myself. The new tweeter is far more open and precise then the Esotar 2.

dial's picture

Probably the best built loudspeakers in the world, look a little like old Goldmund with several boxes.

jeffhenning's picture

I've never thought that Wilson's products are poorly built, just poorly conceived and of incredibly poor value.

When it comes to this latest offering, given that it's only around $30K, it's lack of performance to cost ratio is a few magnitudes of order lower than several other of it's more obscene offerings.

Again, I'm not stating that their speakers don't sound really good. It's just that their value for the dollar is incredibly poor (even more so when you can buy all of the drivers from Madisound). And this is regardless of what ever voodoo they claim to do with their cabinets.

I'm much more impressed by Rockport Technologies designs when it comes to cabinets and drivers.

A friend of mine owns a very rare Bentley (1 of 30). He loves that car, but admits that he might consider auctioning it if Bentley comes out with an electric version. He's 82 years old.

In the next months, my system will include the LS50's I've had for a couple years and then have each sitting atop two, stacked Rythmik L12 servo subs (already have a stereo pair with the LS50's on stands). A Benchmark AHB-2 drives the KEF's and 1,200 watts of UCD amps will power the subs.

Forgetting the raw power spec for the subs (with their much greater output ability & that they can go much deeper and do it cleaner than probably any Wilson), I'm fairly confident that this system, at a sane level and for way less that these Wilson speakers, would be judged as good if not just a hair better... or more.

The drivers that Wilson uses have around 4-5dB greater output for the mids and highs so they may be able to offer a bit higher SPL performance in that arena, but I rarely listen to music over 95dB average @1kHz. The subs I'm using will be pumping out a good bit for the right music, but then this system already laughs at low bass levels like that (over 100dB under 100Hz). Adding two more subs will only make the sub bass even better. And it's fully correlated and temporally aligned with the rest of the speakers (I use Dirac Live). You cannot achieve that with ported, passive speakers.

So, the tally:

• KEF LS50 pair - $1,100
• Rythmik L12 subs (4) - $2,200
• Benchmark AHB-2 - $3,000

Total: $6,300

That leaves a lot of money to figure out how to do the active crossover between the mains and subs. Of course, you do need to know how to do that. If you do not, throwing a ton of money at the problem with passive speakers rather than learning something about audio engineering will not necessarily produce a better result (if at all).

Given the difference in price, you could spend a few grand to have a person design your system and be way ahead. Take your pick of great stuff that costs way less. I offered my list as a point for comparison.

To get back to the car analogy Sasha alluded to, the Wilsons are a Bentley, but it's one that will spell the end of the company as their rich clients die off, DSP becomes ubiquitous to improve loudspeakers and gear lust becomes much less of a thing (equipment as status symbols) amongst more tech savvy youth. They care about performance with ROI as a metric (when they care about performance at all).

Even my Bentley-owning friend likes driving his wife's fun, little, Toyota convertible around town. He also loves that the service bills are 1/10 his Bentley's.

Wilson is Bentley, but without the governance of VW and devoid its forward thinking. Personally, I'd love a C8 Vette with a 200kWhr battery and a supercapacitor as a supplement. That could actually be a thing soon.

By the way, why finding the proper place for these speakers in the room is problematic is because of their innate design flaw: a rear firing port. Not that a forward firing port would be a panacea, but it would help slightly with this design. Wilson's decided to bolster the low end by using the proximity effect of the front/side walls with the port firing towards them, but that also means that the summation in the low end with the relatively in-phase woofers and the inherently out-of-phase rear port (for much of its output) becomes very problematic. It also means that the bass is probably only really smooth at at the ideal listening position. Ported speakers, by design & for efficiency, sacrifice temporal fidelity for low frequency response.

Unfortunately, to gain a perceived flat frequency response and lower distortion around the port resonance, Wilson ceded all other aspects of low end quality with a port design and most especially with a rear port.

If these woofers transitioned a bit higher to the port, it might be less problematic with it being rear firing. That would, then, not offer as much "in-room" bass. No free lunch.

Personally, I'd rather have more powered subs playing with better fidelity in all realms.

Wilson makes no trade-offs when it comes to build quality, but makes a bunch of them when it comes to in-room performance, ease of installation and bang for the buck.

While I'm here, a question: does each one of these things weigh 236lbs or is that the pair? So, another set of Wilson speakers that takes a team of people to install or even get in the house? I guess the upside is that you don't need to knock a giant whole in your mansion for a forklift or crane installation.

georgehifi's picture

"The 8 ohm tap of the MC462 has the lowest output impedance"

Can someone JA? please explain this to me how is it possible, the only thing I can think is that there is much more feedback on the 8ohm than the 4ohm, then what's the use of the 4ohm if not for better bass damping factor (control)?? Won't even mention the 2ohm tap!!!!!!!!!!!

Cheers George

Bogolu Haranath's picture

Higher output impedance = lower feedback = lower damping factor = more tube like sound :-) .......

JRT's picture

A comparison of these Wilson Sasha DAW to his Joseph Audio Pearl 3 might have been both fun and informative. Regardless some superficial external similarity, these are very different loudspeakers due to design choices in drivers and crossovers.

Anton's picture

"To my way of thinking, a more apt analogy for the Sasha DAW would be to a really fine musical instrument, which musicians can and do find a way to have in their lives."

"I have never heard music recreation in my own home like this before. The Sasha DAW has rocked my listening world."

I have to be your enabler on this. They will make your life better.

To paraphrase The Fabulous Fury Freak Brothers: "The Wilsons will get you through times of no money better than money will get you through times of no Wilsons."

Think of them as that fine musical instrument you mentioned.

Sasha Matson's picture

Greetings Anton,
Thanks for your proactive advice here. Other have asked me if I was keeping the 'Sasha DAW's? When they first arrived, I told Wilson Audio I would not discuss any possible purchase until after I filed my review- that just seems the ethical & professional way to go. I did that, and then I indeed did have that discussion. They are here to stay, and they continue to amaze me!
Best Wishes,
Sasha M.

Anton's picture

It was obvious you were meant for each other!

Hearty congratulations!

Bogolu Haranath's picture

Anton ..... Daryl Wilson is waiting for your call ........ He is gonna hand deliver your Sasha DAW and Peter McGrath is gonna set them up in your listening room :-) .........

dravera's picture

Curious if you hooked the Sasha DAW up to the MC275 and the result? My Sasha DAW (in Blue) are arriving next week! I have a pair of MC275's running in mono currently on the Sabrinas. We have very similar systems as I also use a c2300 preamp!

Sasha Matson's picture

Sorry I missed your question until now. I am confident you will have heard great sound with the MC275 / Wilson combo-- right? I did try that, but that description was cut from my review for word count reasons. It sounded great! As John Atkinson and Vern Credille of Wilson both pointed out- the 8 ohm tap off the Macs is a better way to go than using the 4 ohm. Life is full of little mysteries!